BMW 640i xDrive Water Pump Replacement at your home or office.

How do mechanics replace the water pump?

• The water pump is usually bolted to the front of the engine. The replacement procedure will vary depending on whether the pump is driven by the timing belt, the serpentine belt, or chain.
• On a cold engine, the engine coolant is drained to a level below the water pump.
• Components that require removing to access the water pump are removed, including the belt or chain that directly drive the pump.
• The bolts holding the pump to the engine are removed and the pump is pulled out.
• The gasket surface must be cleaned and the pump mounting surface inspected. A new gasket, rubber seal, or RTV sealant, as required, is installed and then the new pump. The bolts are torqued in sequence using a calibrated inch pound torque wrench.
• For applications where the water pump is driven by the timing belt, the timing belt must be removed. Typically, this requires removal of the crankshaft pulley, timing belt covers, and timing belt tensioner. Once the new pump is installed, new coolant is added back while bleeding the cooling system of any air. The engine is then run and brought to normal operating temperature to check for leaks and ensure normal operating temperature.